EnergyHouse design

All-electric, efficient homes reduce energy bills

All-electric, efficient homes reduce energy bills

Howard Elston

Based on my experience, all-electric, efficient homes offer an exciting future for residential dwellings in Australia, particularly when it comes to minimising energy bills.

For my monthly bill in May, I paid $55 for my home’s energy needs. That’s all the electricity and car ‘fuel’ but no gas as there isn’t a gas connection. The 2023 energy bill averaged just over $1 per day.

What is an all-electric home?

My home in Ringwood East fits the Rewiring Australia definition of an all-electric home. All appliances are electrical devices, including the car. Reverse cycle air conditioners provide heating and cooling when required. Hot water is supplied by a heat pump hot water system. Solar panels generate electricity during the day to power household appliances and to recharge the electric vehicle, with a battery meeting night time electricity demand.

What is an efficient home?

I think of efficiency as how well a house uses energy to maintain a comfortable indoor temperature. The more efficient a home, the less energy needed to operate mechanical heating and cooling devices. Sustainability Victoria data shows that almost 50% of a conventional home’s energy goes into heating and cooling so it’s by far the largest contributor to bill shock.

Any home can be made comfortable if the resident is willing to pay for enough energy (gas or electricity) to maintain a comfortable indoor temperature. However, I’d say this is an inefficient home with a large energy bill.

The NatHERS Star rating is a good measure of a dwelling’s efficiency. My 2-bedroom home is a passive solar design, rated at 8.4 Stars out of a possible 10 Stars.

During winter, sunlight streams through the north-facing windows, warming the indoor thermal mass. Excellent insulation reduces external heat loss. On a cold, clear winter’s day, it’s possible sunlight alone heats the interior, eliminating the need for mechanical heating.

In summer, an eave shades the windows, stopping sunlight from warming the concrete slab. Now the insulation reduces internal heat gain so the slab keeps indoors comfortable. If the temperature does rise, turning on the air conditioner is not the first option. Ceiling fans are often enough to supply a cooling breeze. Also, Melbourne’s changeable weather often helps. When a cool change arrives after a hot day, opening all the windows for natural air circulation flushes warm air out of the house. Next morning, closing the windows traps cool air indoors.

Combining all-electric appliances with an efficient house design is an effective combination to deal with cost-of-living pressure from energy bills.

Energy bills are significantly lower

Rewiring Australia estimates the average household can save $3,450 per year over 10 years by changing to an all-electric home. Comparing my annual energy bill of around $400 with the bills paid by others in homes fitted with gas appliances shows the predicted savings are realistic and achievable.

Of course, cutting costs is important, but this shouldn’t be at the expense of indoor comfort. Passive solar design, backed up with an efficient reverse cycle air conditioner ensures the indoor temperature stays within a comfortable range year-round.

I recommend anyone replacing a household appliance (eg gas hot water system or ducted gas heater) or renovating their home consider going all-electric. Anyone contemplating a new build should investigate designing an all-electric, efficient home.